Ischemic heart disease causes mitral regurgitation by the combination of ischemic dysfunction of the papillary muscles, and the dilatation of the left ventricle that is present in ischemic heart disease, with the subsequent displacement of the papillary muscles and the dilatation of the mitral valve annulus.
Stretching of the leaflets of the valve and of the associated chordae tendineae prevents the valve leaflets from fully coapting when the valve is closed, causing the valve leaflets to prolapse into the left atrium. Mitral regurgitation of blood from the left ventricle into the left atrium results in increased total stroke volume and decreased cardiac output, and ultimate weakening of the left ventricle secondary to a volume overload and a pressure overload of the left atrium.
US Patent Application Publication 2005/0004668 to Aklog et al., which is incorporated herein by reference, describes implantable devices and methods for the repair of a defective cardiac valve. The implantable devices include an annuloplasty ring and a restraining and/or a remodeling structure or mechanism. The annuloplasty ring functions to reestablish the normal size and shape of the annulus bringing the leaflets in proximity to each other. A device having a remodeling structure further facilitates remodeling of the valve but allows the use of a flexible ring. The restraining structure functions to restrain the abnormal motion of at least a portion of the valve being repaired. The restraining and remodeling structures may include at least one strut across the interior of the circumference of the ring.
US Patent Application Publication 2005/0171601 to Cosgrove, which is incorporated herein by reference, describes an annuloplasty repair segment and template for heart valve annulus repair. The elongate flexible template may form a distal part of a holder that also has a proximal handle. Alternatively, the template may be releasably attached to a mandrel that slides within a delivery sheath, the template being released from the end of the sheath to enable manipulation by a surgeon. A tether connecting the template and mandrel may also be provided. The template may be elastic, temperature responsive, or multiple linked segments. The template may be aligned with the handle and form a two- or three-dimensional curve out of alignment with the handle such that the annuloplasty repair segment attached thereto conforms to the curve. The template may be actively or passively converted between its straight and curved positions. The combined holder and ring are suited for minimally-invasive surgeries in which the combination is delivered to an implantation site through a small access incision with or without a cannula, or through a catheter passed though the patient's vasculature.
U.S. Pat. No. 6,569,198 to Wilson et al., which is incorporated herein by reference, describes an elongated member that includes distal and proximal segments separated by an intermediate segment. The prosthetic device has at least one anchor control wire to anchor the device in the blood vessel and at least one length control wire. A second preferred embodiment is an elongated member that includes distal and proximal segments that are connected by a pivot or hinge joint. A control wire is anchored on the distal segment and pivotally moves the distal and proximal segments closer together. Rotation of the length control wire of the first embodiment or the control wire of the second embodiment reduces the circumference of the valve annulus.
U.S. Pat. No. 6,102,945 to Campbell, which is incorporated herein by reference, describes a support ring for a natural human heart valve, including a first ring portion having opposite terminal ends and a second ring portion having opposite terminal ends. An interconnector extends through and interconnects the first and second ring portions, to maintain the opposite terminal ends of the first ring portion adjacent the opposite terminal ends of the second ring portion, to form a segmented ring having a first and a second interface between the first and second ring portions. The first ring portion is of a greater length than the second ring portion. The ring portions are separable by severing the interconnector at the first and second interfaces, thus producing two variable size ring segments.
U.S. Pat. No. 6,217,610 to Carpentier et al., which is incorporated herein by reference, describes an expandable annuloplasty ring which may either expand spontaneously, in situ, as the patient grows or be expanded by surgical intervention by balloon dilatation. The distensible annuloplasty ring may be usable in pediatric patients whose growth, subsequent to surgical implantation of the ring, will necessitate subsequent enlargement of the ring to accommodate growth of the annulus. The ring may include relatively expandable segments to enable the enlargement thereof The ring segments may include engaging teeth which cooperate with notches or slots formed in the tubes to provide some resistance to ring distention, while preventing collapse of the ring in the opposite direction. The teeth may be of different sizes or shapes to regulate the amount of force needed to expand the ring at different stages of the patient's growth. Alternatively, the adjustable ring includes a solid core of non-elastic material which plastically retains its shape upon natural expansion of the annulus, or after surgical expansion. In one embodiment, segments are coupled together with a discontinuity around the ring periphery. Pivot regions are provided between adjacent segments that, along with the discontinuity, enable the ring to expand upon annulus growth. The discontinuity may be positioned along the anterior side of the ring or around the posterior side. A further version makes use of telescoped segments with no discontinuity. The segments are coupled together with tubular sheaths, and expand without decoupling. A fabric covering may be omitted.
US Patent Application Publication 2003/0018358 to Saadat, which is incorporated herein by reference, describes techniques for thermally and/or mechanically treating tissue, such as valvular structures, to reconfigure or shrink the tissue in a controlled manner. Mechanical clips are implanted over the leaflets of a valve, e.g., in the heart, either alone or after thermal treatment to cause the valve to close more tightly. The clips are delivered by a catheter and may be configured to traverse directly over the valve itself or to lie partially over the periphery of the valve to prevent obstruction of the valve channel. Alternatively, individual anchors with a tensioning element, like a suture, are described as being useful for approximating the valves towards each other.
US Patent Application Publications 2004/0260393 to Rahdert et al. and 2004/0127982 to Machold et al., which are incorporated herein by reference, describe techniques using an implant that is sized and configured to attach in, on, or near the annulus of a dysfunctional heart valve. In use, the implant extends either across the minor axis of the annulus, or across the major axis of the annulus, or both. The implant is described as restoring to the heart valve annulus and leaflets a more functional anatomic shape and tension. The more functional anatomic shape and tension are conducive to coaptation of the leaflets, which, in turn, reduces retrograde flow or regurgitation. In some embodiments, the implant is configured to rest at or near a heart valve annulus and apply a direct mechanical force along the minor axis of the annulus to inwardly displace tissue toward the center of the annulus. For some applications, the implant is configured to extend significantly above the plane of the valve, while for other applications, the implant is configured to extend a short distance above the plane of the valve.
PCT Publication WO 01/26586 to Seguin, which is incorporated herein by reference, describes a device comprising: an implant with an elongated deformable structure, such that the implant can adopt an elongated shape to be inserted into the patient's body through a passage of reduced diameter and a curved shape adapted to perform annuloplasty; and a tubular instrument for receiving at least partly said implant therein, having a rigidity such that it enables the implant to be inserted in the patient's body through said passage; said instrument comprises an orifice at its distal end, providing access to the implant, means for locking the implant in rotation relative thereto, means for maintaining the implant relative thereto, and means for locating its angular orientation inside the patient's body. The device is described as being designed for use in the reconstruction of cardiac valves.
U.S. Pat. No. 5,593,424 to Northrup III, which is incorporated herein by reference, describes an apparatus and method for reducing the circumference of a vascular structure comprising the steps of providing a plurality of sutures and a plurality of discrete suture support segments of a biocompatible, inert material, each suture support segment having at least two suture holes spaced a predetermined distance (D) apart; individually suturing each discrete suture support segment to the vascular structure with one of the plurality of sutures by effecting a horizontal mattress (U-shaped) suture along the vascular structure through a length of tissue of the vascular structure such that the length (D′) of tissue sutured is greater than distance (D); and tightening and tying off the suture, whereby each sutured suture support segment creates an imbrication in the vascular structure, thereby reducing the circumference thereof. A biocompatible, inert stabilizing material is described as being optionally affixed over the suture support segments and the vascular structure prior to tying off the suture to stabilize the interval between the suture support segments and eliminate direct exposure of the segmented apparatus to blood.
U.S. Pat. No. 3,656,185 to Carpentier, which is incorporated herein by reference, describes a cardiac valvular prosthesis, e.g., for the mitral valve, consisting solely of an annular or part-annular member adapted to fit against the base of the cusps of a human heart valve, and suture means for securing the member in place. The prosthesis cooperates with the natural valve cusps of the patient to form the valve.
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The following articles, which are incorporated herein by reference, may be of interest:
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